gcc/testsuite/gcc.target/aarch64/vect-widen-sub.c

/* { dg-do run } */
/* { dg-options "-O3 -save-temps" } */
#include <stdint.h>
#include <string.h>

#pragma GCC target "+nosve"

#define ARR_SIZE 1024

/* Should produce an usubl */
void usub_opt (uint32_t *foo, uint16_t *a, uint16_t *b)
{
    for( int i = 0; i < ARR_SIZE - 3;i=i+4)
    {
        foo[i]   = a[i]   - b[i];
        foo[i+1] = a[i+1] - b[i+1];
        foo[i+2] = a[i+2] - b[i+2];
        foo[i+3] = a[i+3] - b[i+3];
    }
}

__attribute__((optimize (0)))
void usub_nonopt (uint32_t *foo, uint16_t *a, uint16_t *b)
{
    for( int i = 0; i < ARR_SIZE - 3;i=i+4)
    {
        foo[i]   = a[i]   - b[i];
        foo[i+1] = a[i+1] - b[i+1];
        foo[i+2] = a[i+2] - b[i+2];
        foo[i+3] = a[i+3] - b[i+3];
    }
}

/* Should produce an ssubl */
void ssub_opt (int32_t *foo, int16_t *a, int16_t *b)
{
    for( int i = 0; i < ARR_SIZE - 3;i=i+4)
    {
        foo[i]   = a[i]   - b[i];
        foo[i+1] = a[i+1] - b[i+1];
        foo[i+2] = a[i+2] - b[i+2];
        foo[i+3] = a[i+3] - b[i+3];
    }
}

__attribute__((optimize (0)))
void ssub_nonopt (int32_t *foo, int16_t *a, int16_t *b)
{
    for( int i = 0; i < ARR_SIZE - 3;i=i+4)
    {
        foo[i]   = a[i]   - b[i];
        foo[i+1] = a[i+1] - b[i+1];
        foo[i+2] = a[i+2] - b[i+2];
        foo[i+3] = a[i+3] - b[i+3];
    }
}


void __attribute__((optimize (0)))
init(uint16_t *a, uint16_t *b)
{
    for( int i = 0; i < ARR_SIZE;i++)
    {
      a[i] = i;
      b[i] = 2*i;
    }
}

int __attribute__((optimize (0)))
main()
{
    uint32_t foo_arr[ARR_SIZE];
    uint32_t bar_arr[ARR_SIZE];
    uint16_t a[ARR_SIZE];
    uint16_t b[ARR_SIZE];

    init(a, b);
    usub_opt(foo_arr, a, b);
    usub_nonopt(bar_arr, a, b);
    if (memcmp(foo_arr, bar_arr, ARR_SIZE) != 0)
      return 1;
    ssub_opt((int32_t*) foo_arr, (int16_t*) a, (int16_t*) b);
    ssub_nonopt((int32_t*) bar_arr, (int16_t*) a, (int16_t*) b);
    if (memcmp(foo_arr, bar_arr, ARR_SIZE) != 0)
      return 1;
    return 0;
}

/* { dg-final { scan-assembler-times {\tusubl\t} 1} } */
/* { dg-final { scan-assembler-times {\tusubl2\t} 1} } */
/* { dg-final { scan-assembler-times {\tssubl\t} 1} } */
/* { dg-final { scan-assembler-times {\tssubl2\t} 1} } */